Well, IMO there's a ton of low quality made-in-china jacks out there. The GOOD ones tend to be over $400. The quality of the Torin jacks and others seems to be very spotty. I bought one from Pep Boys, and it wasn't long before the seal blew out. Now it won't lift anything, and I haven't gotten around to doing anything with it.
Here's a long thread on the subject:
aluminum racing jacks. $99.99 + Official "Floor Jack Tech" Thread - Page 13 - Corner-Carvers Forums